"Before there were island universes, there was Tycho's island, where a new kind of observatory and research institution linked a Danish island to the planets and stars. What I love best about John Christianson's book is the level of detail his scholarship probes. If you want to know who taught the incomparable Tycho his trigonometry or who engineered the hydraulic system that delivered running water to all the rooms in the castle of Uraniborg, you'll find their names and follow their lively adventures here." Dava Sobel, author of Longitude and Galileo's Daughter